I
One side: the gods take no notice
Epicurus held that the gods are so far removed from human affairs that they neither harm us nor help us. He did not conclude that one should stop praying — but on his account prayer cannot be a transaction, because there is no one on the other end of it.
Plato took the opposite view and took it hard: to say that the gods have no care for people is itself a form of impiety, to be avoided.
The gods are not to fight for the cowardly; for the law of the cosmos lays down that in war life is kept by valour and not by prayers. Nor are the fruits of the earth got by prayers; they come by labour.
Plotinus, Enneads 3.2.8
II
Ask for what is possible
Between the two extremes there is a practical tradition, and its rule is short. One of the Delphic maxims runs: pray for what is possible. Not because the gods are weak, but because they govern the order of things and do not break it — and a request that requires the order to break is a request that cannot be granted.
Pythagoras is reported to have gone further and forbidden his followers to pray for anything definite for themselves, on the ground that they do not know what is good for them. The best prayer, on that view, names no object at all.
III
The end of the argument, and the other end
Cleanthes carries the philosophical answer as far as it goes. His long hymn spends thirty-seven lines describing a world governed throughout by law, and then asks for one thing only: understanding of that law. His four-line prayer asks for nothing whatever — lead me where I am assigned; if I refuse I shall follow anyway.
And on the same shelf, from the same centuries, lies a magician's notebook in which nobody asks at all. There the god is named twenty ways not out of reverence but to be sure of the grip, and the words are meant to compel. The corpus holds both, a few clicks apart, because antiquity did.
IV
Why this page does not answer the question
Because antiquity did not. A modern reader is usually offered one answer — most often a devotional one, written now and presented as what the ancients believed. This collection would rather show the disagreement, which is both truer and a great deal more interesting than any of the positions in it.